1. Field of the Invention
The present invention generally relates to a device and method for clearing obstructions in surf zones. More particularly, the device and method relates to clearing obstacles and mines by sundering the subsoil beneath and alongside the obstructions in a surf zone, thereby eliminating subsoil support from beneath the obstruction, and causing the obstruction either to drop away from the surface of the water or to float away. Most particularly, the device and method facilitate successful amphibious operations by clearing obstructions within the transit path of landing vehicles and/or naval support vessels.
2. Description of the Related Art
Military amphibious assault operations require the movement of large numbers of troops and massive amounts of supplies into a confined shore area, such as a beach, over a short period of time. Generally, these amphibious assaults are conducted in areas occupied by opposing military forces. In defending against an amphibious attack, the opposing military forces may place non-explosives obstacles, such as artificial barriers or reefs, concrete cubes, log posts, steel hedgehogs, steel tetrahedrons, sea urchins, wire and the like, within the surf zone of an expected line of assault to impede efficient movement of landing craft traveling to the shore. In using man-made non-explosive obstacles, defending forces attempt to delay the amphibious assault and/or channelize an assault into a defended area. Interrupts in the movement of troops and supplies across the surf zone to the shore may result in a significant disadvantage, including loss of personnel and equipment, to the assaulting forces.
Additionally, amphibious assault operations may necessarily cross surf zone areas having naturally occurring obstacles within a transit path of assault boats to the shore. The obstacles may be coral, rocks, or other large objects or protrusions in the water which are hazardous to speeding landing craft carrying heavy equipment and troops. These naturally occurring obstacles protrude into the path of advancing landing craft, impeding their transit, possibly disabling or sinking the landing crafts and/or support vessels.
Another hazard to an amphibious assault operation is deployed mines. The removal of mines is a particularly difficult endeavor. Mines are conventionally used to impede the progress of military forces through an area, either sea or land. Used against an amphibious assault within a surf zone, mines are particularly troublesome for the successful completion of the assault. Selective placement of mines within the surf zone may hinder or halt the transit of landing craft to shore.
All of these obstructions, man-made non-explosive obstacles, naturally occurring obstacles and/or mines may force advancing troops to by-pass the most expeditious transit route through a surf zone, causing delays, loss of surprise, and/or the loss of a concentrated advancing amphibious force. With the loss of force concentration, an advancing force may receive high rates of casualties and/or lose military advantage against the defending forces.
Several approaches to obstacle and mine clearance are known. U.S. Pat. No. 5,661,258 (Garcia et al.) discloses an air-delivered ordnance explosive for clearing navigable sea channels. U.S. Pat. No. 5,598,152 (Scarzello et al.) discloses an underwater vehicle that detects possible mine locations and deposits mine-clearing explosives close-by. U.S. Pat. No. 5,437,230 (Harris et al.) discloses a standoff mine neutralization system using an unpowered air vehicle. U.S. Statutory Invention Registration no. H162 (Sullivan, Jr. et al.) discloses a system for wide-area mine clearance using multiple fuel-containing containers.
However, these approaches are deficient when used for surf zone operations. First, amphibious assault operations require an unannounced assault in a given area. By limiting the amount of time the enemy knows of the assault, enemy forces are denied preparation time to reposition armaments and defense positions during the amphibious onslaught. Second, rapid execution of the amphibious operation is required to deny a defending force use of its reserve forces. Third, the successful destruction of an obstruction with conventional explosives depends partly on the composition of the obstruction. Fourth, destruction of obstructions requires the detonation of high yield explosives. These explosives are dangerous to handle and move, complicating their use in training and operational use. Additionally, the high yield explosives are environmentally hazardous, further complicating training for the safe use of the explosives. Fifth, a device and method which are useful against man-made and natural obstacles are needed, because the rapidly evolving military situation before and during an amphibious assault may not allow the amphibious forces time to identify the particular type of obstruction. Sixth, high yield explosives create significant crater or berms along the subsoil surface which create hazards for landing vehicles within the surf zone. Accordingly, none of the identified techniques provide for reliable clearance of man-made non-explosive obstacles, naturally occurring obstacles and mines in surf zones during amphibious assault operations.
In view of the foregoing, improvements in clearing obstructions in surf zone areas have been desired. In addition to improved reliability of clearing both obstacles and mines from landing craft transit paths, it has been desired to provide a device which is relatively safe to deploy.
The present invention addresses these needs.